Technical Field
The invention concerns a press roll with adjustable flexion, preferably intended for use in the paper industry. The press roll has a hollow shell that can rotate around a fixed yoke and, in conjunction with a mating roll, form a .[.web.]. .Iadd.nip.Iaddend., e.g. press nip for a web of paper, to travel through. The axis of rotation of both rolls lie in the same press plane as the press nip. The press roll has the following additional characteristics:
(a) A self-aligning bearing keeps each end of the shell at least indirectly away from the yoke. PA1 (b) There is a hydraulic support in the shell near the press .[.rip.]. .Iadd.nip .Iaddend.that transfers support forces from the yoke to the shell along the press plane. PA1 (c) Each end of the yoke rests directly on support caps. PA1 (d) The longitudinal distance between the center planes of the supported areas of the yoke (the planes being perpendicular to the axis of rotation of the rolls,) is .[.no longer than and preferably just as long as.]. .Iadd.at most somewhat greater than .Iaddend.the distance between the mating-roll bearings. PA1 1. Das Papier, 1980, 5, pp. 165-71, PA1 2. German Auslegeschrift 2 407 510 corresponding to U.S. Pat. No. 3,932,921, PA1 3. U.S. Pat. No. 3,119,324, PA1 4. German Offenlegungsschrift No. 2 503 051, PA1 5. U.S. Pat. No. 3, 276,102, PA1 6. German Auslegeschrift No. 2 418 431 corresponding to U.S. Pat. No. 3,949,455, PA1 7. U.S. Pat. No. 3,766,620, and PA1 8. German Auslegeschrift 2 826 316 corresponding to U.S. Pat. No. 4,213,232. PA1 1. The supplemental supports are not activated. The shell bends along the normal line of flexion. The hydraulic pressure in the main support can still be varied to make the press in the nip exactly uniform, heavier in the middle, or heavier at the edges. PA1 2. The supplemental supports act against the direction of press and the hydraulic pressure in the main support is slightly increased. The result is uniform press along a wide middle range and more press at the edges. If the hydraulic pressure in the main support is further increased, a smooth press profile at the edges and a peak pressure in the middle will be obtained. PA1 3. The supplemental supports act in the direction of press and the hydraulic pressure in the main support is slightly reduced. The result is heavy pressing along a wide middle range and reduced pressing at the edges. If the pressure in the main support is reduced even more, a smooth press profile at the edges and reduced pressure in the middle will be obtained.